Re: Is there a trademark issue here?

Trademark priority in the US is based on first use. Thus, if one company was the first to use the mark in commerce then it has priority over the other company. Based one what you've shown, assuming that these are separate companies and there is no license between them, there is a problem because consumers seeing one product will assume there's a relationship between the two upon seeing the second product (even though the bottles are different, the names are very similar and they're related products). Finally, if the first user was only using the trademark in a limited geographical area, then the filing of a trademark registration by the second company might give it national rights over the first company in other geographical areas.

Re: Is there a trademark issue here?

Different looking labels, one is Stalk and one is Stock. Less similar than St. George's English Malt Whisky and St. George's American Single Malt. I'm not an attorney, but there doesn't seem to be much similarity other than homophonic names.